An efficient methodology to obtain novel antifungal analogs of brassinin 1 is described. Starting from L-tryptophan 2, N,N -dialkylthiourea 4, 4-[(1H-indol-3-yl)methylene]-2-sulfanylidene-1,3-thiazolidin-5-one 5 and alkyl (2S)-3-(1H-indol-3-yl)-2-{[(alkylsulfanyl)carbonothioyl]amino} propanoate 6 type compounds were obtained as main products in different ratios depending on the reaction conditions via a tandem dithiocarbamate formation and Michael addition reaction. In order to understand the dependence of the reaction conditions on the mechanism pathway, a DFT/B3LYP study was performed. The results suggested the existence of competitive mechanistic routes which involve the presence of an ionic dithiocarbamate intermediate 9. Antifungal activities of all products were then evaluated against Fusarium oxysporum through mycelial growth inhibition using a microscale amended-medium assay. IC 50 values were thus determined for each compound. These results showed that 6-related compounds can be considered as promissory antifungal agents.

A high-yielding, green, and fast synthesis of alkyl 2-substituted {[(alkylsulfanyl)carbonothioyl]amino}acetate-type compounds is described. The one-pot, three-component condensation of alkyl 2-aminoesters, carbon disulfide, and electron-deficient olefins was the key reaction to be developed. The products were obtained easily and efficiently, with good overall yields after two steps (79–91%), employing short reaction times, without the use of a catalyst, and ultrasonic irradiation in water. This procedure was exploited to produce antifungals against the phytopathogenic fungus Fusarium oxysporum . Some synthesized compounds exhibited good performance as mycelial growth inhibitors (IC 50 < 80 μM). Structural and antifungal datasets were integrated to explore the comprehensive three-dimensional quantitative structure–activity relationship (3D-QSAR) using comparative molecular field analysis (CoMFA) and explain the observed activity. This integration resulted in an excellent CoMFA model ( r 2 = 0.812; q 2 = 0.771) after substructure-based alignment. According to this model, synthesized compounds possessing steric bulky electron-withdrawing groups in the dithiocarbamate moiety can be considered as promising F. oxysporum inhibitors.

In this paper, we describe the solvent-free three-component synthesis of 2,4,5-trisubstituted-1H-pyrrol-3-ol-type compounds from L-tryptophan. The first step of the synthetic methodology involved the esterification of L-tryptophan in excellent yields (93–98%). Equimolar mixtures of alkyl 2-aminoesters, 1,3-dicarbonyl compounds, and potassium hydroxide (0.1 eq.) were heated under solvent-free conditions. The title compounds were obtained in moderate to good yields (45%–81%). Density functional theory using “Becke, 3-parameter, Lee–Yang–Parr” correlational functional (DFT-B3LYP) calculations were performed to understand the molecular stability of the synthesized compounds and the tautomeric equilibrium from 3H-pyrrol-3-one type intermediates to 1H-pyrrol-3-ol type aromatized rings.

Schiff bases are widely used molecules due to their potential biological activity. In this manuscript, we presented the synthesis and NMR study of new enamine Schiff bases derived from l -tryptophan, showing that the Z-form of the enamine is the main tautomeric form for aliphatic precursors. The DFT-B3LYP methodology at the 6-311+G**(d,p) level suggested that the tautomeric imine forms are less stable than the corresponding enamine forms. Their isomerism depends on the formation of intramolecular hydrogen bonds and steric factors associated with the starting carbonyl precursors. The in vitro biological activity tests against Fusarium oxysporum revealed that acetylacetone derivatives are the most active agents (IC 50 < 0.9 mM); however, the antifungal activity could be disfavored by bulky groups on ester and enamine moieties. Finally, the structure-based virtual screening through molecular docking and MM-GBSA rescoring revealed that Schiff bases 3e , 3g , and 3j behave putatively as binders for target proteins involved in the life processes of F. oxysporum . In this sense, molecular dynamics analysis showed that the ligand–protein complexes have good stability with root-mean-square deviation (RMSD) values within the allowed range. Therefore, the present study paves the way for designing new antifungal compounds based on l -tryptophan-derived Schiff bases.

Cocoa pulping currently is a process that is developed manually in several regions of Colombia, due to many farms do not have enough technology to develop the cutting and pulping of the cocoa pod, which generates delays, low performance, low quality of the cocoa derives products and economic losses. The Quality Function Deployment (QFD) method and Bibliometric analysis (BA) were applied to designing a machine for cocoa pulping for a farm in Cesar, Colombia. Firstly, a Bibliometric analysis was developed to visualize trends and hot keywords, countries, and clusters related to the Cocoa and Quality of this essential agricultural branch worldwide of scientific obtaining publication details from the Scopus database. Secondly, the QFD method was applied to translate the customer requirements into detailed requirements to perform a low-cost machine, eco-friendly, versatile, and easy to use. Finally, the design results validation was carried out through the finite analysis method using Ansys and Solidworks CAD software. The BA results show that cocoa processing is an important topic worldwide, with a fastgrowing of 2.59% in the last 76 years, where around 5800 authors have been published articles related to cocoa and quality subject in different ways. From QFD results and simulations obtained on the structure of the machine of AISI 304 steel, this material supports the stresses and deformations generated in the regular use of the machine (4700 pods per hour), guarantying the satisfaction of the customers, and above all the cocoa quality and the economy of the farm producers of cocoa beans in Colombia. Finally, the results obtained demonstrate that the QFD method is a valuable tool to knowing the needs and requirements of the customers and translate thus to engineering specifications where the design group develops different proposals taking into account costs, safety, and performance of the machine through modern computational CAD software and design theories.

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Las fuentes de agua potable, necesarias para garantizar la salud de los seres vivos y el medioambiente, son cada vez más escasas. Esta grave problemática exige el desarrollo de nuevas tecnologías eco-amigables que permitan el monitoreo de metales pesados, la prevención y, especialmente, la remediación de fuentes hídricas contaminadas. Dada la necesidad de orientar las investigaciones hacia el diseño de materiales capaces de retener o facilitar la eliminación de contaminantes con alta eficiencia y efectividad, en este artículo se presentan algunos de los últimos avances respecto al desarrollo de nuevos métodos de remediación de agua empleando bases de Schiff, una familia de moléculas de gran importancia en química. Los resultados de estas investigaciones demuestran su capacidad quelatante y como agente catalizador, en especial, su potencial aplicación para fines ambientales, siendo aún un conjunto de investigaciones incipien-tes, con mucho por explorar en este campo de la ciencia y la ingeniería.